Fluid, gas and material movement may create streams and flows of materials which abrade, degrade, fatigue and wear out a wide variety of components of apparatus. Wear may be caused by friction, impact, pulsation, wave action, grinding, and other actions by a material, fluid and gas flow (collectively, "material flow") against, across, and around one or more surfaces of a component in an apparatus. Regardless of the precise nature or function of an apparatus in which components are subjected to wear by a material flow, wear causes repair and replacement of components, and delays in use of the apparatus while one or more worn components is identified, inspected, removed, and replaced. Wear of components adds to the expense of maintaining and operating the apparatus. Such delays, costs and expenses are compounded if the apparatus in which wear occurs is located at a remote site.
For example, a wide variety of impact crushers are used in commerce to reduce the size of larger earth materials to smaller sized and shaped aggregate. The construction industry trades employ a variety of impact crushers to reduce large aggregate to aggregate sizes and shapes required to satisfy construction specifications for mixtures and admixtures of aggregate with cement and other ingredients, and for further processing of size reductions, chemical leaching, and other stages of use. Construction industry use of impact crushers is but one example of the need to reduce wear by a materials flow in apparatus used to affect the size of particles in the materials flow, to make substantially uniform the size of particles in a materials flow, and to prepare materials for further processing.
Generally, impact crushers provide a device for introducing aggregate into a device for crushing the aggregate. Most impact crushers are designed to rely on centrifugal force to disperse large aggregate through the crusher, and to impact the aggregate against a wide variety of impact crusher components to break up, reduce in size, and ultimately eject from the crusher, aggregate composed of desired shapes, sizes and consistency. Intense efforts have been devoted to improvements in the design and construction of components of impact crushers to reduce the cost of acquiring and operating crushers, to enhance wear resistance of the component parts of crushers, and to facilitate rapid replacement of worn parts of crushers to enable the user of crushers to lose the least possible amount of time during which a crusher is inoperative due to worn parts.
Such improvements are exemplified by those shown in U.S. Pat. No. 3,955,767 issued May 11, 1976 to Mason R. Hise, and U.S. Pat. No. 4,690,341 issued Sep. 1, 1987 to Mason R. Hise and Neil R. Hise, the latter being one of the inventors herein (collectively, the "Hise Patents"). The Hise Patents are instructive on the number and variety of components which may be included in an impact crusher and consequently exposed to wear during operation of an impact crusher. All components of an impact crusher exposed to a material flow of aggregate as exemplified in the Hise Patents, and other impact crushers, are subject to abrasion, decomposition, fracture, friction, impact, pulsation, wave action, grinding, and other actions causing wear to components of an impact crusher is due to the velocity, acceleration and composition of aggregate flows against, across and around the components during operation of a crusher (collectively, "wear"). For example, an impeller of an impact crusher may receive and hurl aggregate against one or more crusher components generally known in the art as anvils. An impeller of an impact crusher is known to rotate at speeds from about 500 to about 2000 RPM. The rotation of an impeller, in combination with centrifugal force, creates a material flow of aggregate consisting of a variety of sizes and shapes of aggregate being projected at, over and around many of the components of the crusher. It is significant that persistent wear occurs not just on anvils, which are designed to cooperate with other crusher components in crushing aggregate, but also on any other component of an impact crusher which may be exposed to the aggregate flow during operation of the crusher.
As a result of persistent wear caused by material flows, components of crushers must be replaced. Replacement of components causes "down time" to repair, refit, and replace components. Additional expenses are associated with replacing the worn part or component, inventorying replacement components, and delivering a replacement component to what is often a remote site, to say little of the general frustration associated with having to stop the aggregate crushing process to replace worn components.
In addition to an impeller included in an impact crusher, an impact crusher may include a housing containing a rotatable impeller assembly. An impeller may include but are not limited to one or more impeller tables, one or more impeller covers, and brackets holding and connecting the tables and covers. An impact crusher may be designed to use shoes attached to an impeller assembly. The shoes, in combination with centrifugal force, hurl and direct an aggregate flow generated by operation of an impeller assembly against one or more anvils located within the crusher. One or more anvils assist in crushing, breaking up and reducing in size the aggregate material in the aggregate flow. The crusher housings, impeller tables, impeller plates, brackets, shoes and anvils, as well as all other components of an impact crusher which cooperate with such components, are subject to wear by aggregate flows. As will be clear to one skilled in the art, crushers may include a wide variety of other components which may be exposed to and impacted by aggregate, causing significant wear in those components.
What is needed, therefore, is a device for reducing wear of components of apparatus exposed during operation to a material flow. Particularly what is needed is a device for reducing wear of components of an impact aggregate crusher during operation by a material flow of aggregate.
In light of the above, it is an object of the present invention to provide a plate and surface which, when exposed to material flows during operation of impact crushers, will increase wear life of components by resisting wear by a material flow across, over and around the plate and surface of the plate.
However, cost also is a significant consideration. The components of impact crushers, for example, could be manufactured of alloys of metals which would be virtually nondegradable, but the cost of manufacturing and buying such components would be prohibitive. Therefore, it is another object of the present invention to provide a plate for reducing wear of components of impact crushers during operation which is cost effective and economical.
Another object of the present invention is to provide a plate for reducing wear to components which is composed of metals and metal alloys rather than materials which may be merely elastomeric.
Yet another object of the present invention is to provide a plate for reducing wear to components which is a complete body rather than merely elements or subassemblies which require assembly or bonding by chemical or mechanical means into an assembly for use to reduce wear by a material stream.
Still another object of the present invention is to provide a plate for reducing wear of components of impact crushers during operation, and a method for manufacturing a device for reducing wear of components of impact crushers during operation, which respectively are easy to use and to practice, and which are cost effective for their intended purposes.
These and other objects, features, and advantages of such a plate for reducing wear by a material flow will become apparent to those skilled in the art when read in conjunction with the accompanying following detailed description, drawing figures, and appended claims.